The present invention relates to a facsimile apparatus, and more particularly to a facsimile apparatus having an automatic facsimile/telephone switching function.
Conventionally, a facsimile apparatus is known which, to allow a telephone line to be used as both a facsimile apparatus (hereinafter referred to as the FAX) and a telephone, is provided with an automatic FAX/TEL switching function. The automatic FAX/TEL switching function realizes the following operation.
As shown in FIG. 4, in a normal state, a telephone 24 is connected to a telephone line 21 via a switching device 23. If it is now assumed that a call is received via the telephone line 21 at a timing t0 shown in FIG. 5, a timer 22 starts counting. If the telephone is hooked off within a predetermined time (between timings t0-t1 in FIG. 5), the received call is connected to the telephone 24. However, unless the telephone is hooked off within the predetermined time, the switching device 23 is switched over to the FAX 25 side by a time-up signal from the timer 22. If the telephone line 21 is connected to the FAX. 25, the FAX 25 starts communication with a distant apparatus in accordance with a predetermined protocol.
The above-described automatic FAX/TEL switching function is provided on G2/G3 FAX which are presently connected to a public telephone network.
In recent years, active use has been made of ISDN networks, and it is conceivable that the above-described automatic FAX/TEL switching function will also come to be provided on the G2/G3 FAX which are connected the ISDN networks. As is known, there are cases where the D-channel protocol of the ISDN includes high layer compatibility (HLC) for designating a type of terminal of communication. In the case where the high layer compatibility HLC includes an attribute for setting the party at the other end of the line to be a telephone or setting the same to be G2/G3 FAX.
However, if the G2/G3 FAX connected to an ISDN network is provided with the above-described automatic FAX/TEL switching function, there has been a drawback in that since the automatic FAX/TEL switching function operates regardless of whether or not the aforementioned high layer compatibility HLC is present, if the G2/G3 FAX is designated by the high layer compatibility HLC, time is wasted until that FAX is connected. Specifically, there has been the problem that the time duration of t0-t1 mentioned above is wasted.
In addition, there is a problem in that if a changeover is effected from the telephone 24 to the G2/G3 FAX 25 by the switching device 23 at the timing t1, when the distant apparatus is telephone, the connection therewith may end unsuccessfully.